Re: [sqlalchemy] alembic (1.4.2) revision --autogenerate hang

[Mike Bayer]

this is due to concurrent database connections where one or more of them has acquired a lock on a schema object such as a Table and other DDL operations against that object are blocked.

look at your processlist on the database server, or run a query against pg_stat_activity on the database itself, to see what other transactions are currently in progress.

it is very possible that the multiple connections are originating from your own application, if there is some kind of double-connection pattern going on, or that there is simply some other application somewhere holding onto database locks like a SQL console.    The pg_stat_activity table should give you a clue where this is happening.

On Thu, Jun 18, 2020, at 1:39 PM, Rob Schottland wrote:

I'm trying to do  "alembic revision --autogenerate"

I get the usual warnings (that I've gotten in previous successful runs)

Here's the console output

alembic$ alembic revision --autogenerate

INFO  [alembic.runtime.migration] Context impl PostgresqlImpl.

INFO  [alembic.runtime.migration] Will assume transactional DDL.

/home/rschottland/.local/share/virtualenvs/astorb_db-u7fxujye/lib/python3.7/site-packages/sqlalchemy/dialects/postgresql/base.py:3010: SAWarning: Did not recognize type 'point' of column 'point_ra_dec'

  "Did not recognize type '%s' of column '%s'" % (attype, name)

INFO  [alembic.ddl.postgresql] Detected sequence named 'units_id_seq' as owned by integer column 'units(id)', assuming SERIAL and omitting

/home/rschottland/.local/share/virtualenvs/astorb_db-u7fxujye/lib/python3.7/site-packages/sqlalchemy/dialects/postgresql/base.py:3331: SAWarning: Predicate of partial index ix_nea_elements ignored during reflection

  % idx_name

INFO  [alembic.ddl.postgresql] Detected sequence named 'editorial_notices_id_seq' as owned by integer column 'editorial_notices(id)', assuming SERIAL and omitting

INFO  [alembic.ddl.postgresql] Detected sequence named 'taxonomy_sys_type_id_seq' as owned by integer column 'taxonomy_sys_type(id)', assuming SERIAL and omitting

After this, alembic appears to be hung...

Any thoughts on what could be the cause? How might I debug this situation?

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